Thermodynamics of one and two-qubit nonequilibrium heat engines running between squeezed thermal reservoirs

TL;DR

This paper investigates one and two-qubit quantum Otto heat engines interacting with squeezed thermal reservoirs, highlighting the advantages of two-qubit systems, the influence of squeezing on performance, and the ability to switch modes via squeezing parameters.

Contribution

It introduces a detailed analysis of two-qubit quantum heat engines with squeezed baths, revealing their higher power output and mode-switching capabilities compared to one-qubit engines.

Findings

Two-qubit engines outperform one-qubit engines in power output.

Squeezing parameters exponentially increase the effective temperature of baths.

Engine mode can be tuned to refrigerator mode by adjusting squeezing parameters.

Abstract

Quantum heat engines form an active field of research due to their potential applications. There are several phenomena that are unique to the quantum regime, some of which are known to give these engines an edge over their classical counterparts. In this work, we focus on the study of one and two-qubit finite-time Otto engines interacting with squeezed thermal baths, and discuss their important distinctions as well as the advantage of using the two-qubit engine. In particular, the two-qubit engine offers an interesting study of the interplay between the degree of squeezing and that of the coherence between the two qubits. We find that the two-qubit engine generally yields higher power than its one-qubit counterpart. The effective temperature of the squeezed baths can be calculated both for the one and two-qubit engines, and they tend to show an exponential growth with increase in squeezing parameters $r_h$ and $r_c$. It is also observed that by tuning the squeezing parameters, the machine can be made to work either in the engine or in the refrigerator mode. Additional effects due to the change in the inter-qubit separation have been studied.